DIY LEDs - The write-up

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Heatsink

Heatsink

I have seen several people post that they are using "C" channel aluminum as a heat sink. So here is my question. Should I use 1" or 3/4". I have post the pics of both below. The 1" comes at 4X the cost of the 3/4". The 1" is ~$20 for 4' and the 3/4" is $10 for 8'. Both can be found at Home Depot. Lowes did not carry these.

The 1" is also square so I would need to cut off one side with the table saw.

Here are the pics:

1" on top:
IMG_3188.jpg


1"
IMG_3189.jpg


3/4"
IMG_3190.jpg
 
Why cut off 1 side of the square stock? I my eyes it's more material to help dissipate heat. Use a small fan to blow air through the tube is active cooling is needed. I don't see any immediate need to cut one side off.

Scott
 
My tought was to sut off one side so I could better dissipate the heat. If I keep it as a square, the air in the middle would be hotter than the outsides.

If I did keep it as a square I could place one of these fans on the end to blast air through.

BM5115-04W-B40-L00_tmb.jpg
 
my brain starting thinking this evening, so a question. I plan on running 8 LEDs on a meanwell eln-60-48D. Since the meanwell puts out 48V, and the LEDs are to run at ~3.3V, should I stick a resistor in series with the LEDs to take up the rest of the potential?
 
The order has been placed. Think I ran that nano place dry of 48D's!

The order has been placed. Think I ran that nano place dry of 48D's!

Thanks for all the input guys. I am looking forward to getting this thing together. I raised the bulb setup to 36 per section (24 Royal Blues and 12 Cool Whites) for 108 LED's total. I will be using 9 total ELN-60-48D's for all the sections and heat sinks ordered from Heatsinkusa. I will be using NOCTUA fans because they provide High CFM at a very quiet db level. Now I ordered the optic mounts so that if I have to play with the optics, I can easily remove them and replace them with others. Each section will be 16 x 16. Each to replace a 250W HQI Metal Halide retro a was going to buy. Man that would have been the way cheapest way out. This mess is costing a pretty penny! Fun times!
 
'The 1" is also square so I would need to cut off one side with the table saw.'

I Definitely say the U-channel is better than just an L-angle.
More mass & more surface area.

Although the 3/4" looks interesting, how thick is it?
I usually drill & tap & want a little more thickness then if you are gluing.

Stu
 
stugray said:
I Definitely say the U-channel is better than just an L-angle.
More mass & more surface area.
Click to expand...

I would be cutting one side off so it would still be a U.



stugray said:
Although the 3/4" looks interesting, how thick is it?
Click to expand...
~1/16"

stugray said:
I usually drill & tap & want a little more thickness then if you are gluing./QUOTE]
I am torn between epoxy and the thermal tape. Even though I will have a splash guard, I am worried about the tape holding up over time.

As for screwing them, that is a lot of holes. I considered stud welding, because a friend of mine does it, but again, a lot of studs to add. The epoxy/tape is much easier.
Click to expand...
 
Grim:

http://alreco.biz/

$30 for 16 feet of 1X1 U-channel - Brighton....

If you need it cut & drilled & tapped, just bring beer & the PAR meter.

Hurry the wife is gone for the rest of the week & the dancing girls are free......;-)

Stu
 
Last edited:
crvz said:
my brain starting thinking this evening, so a question. I plan on running 8 LEDs on a meanwell eln-60-48D. Since the meanwell puts out 48V, and the LEDs are to run at ~3.3V, should I stick a resistor in series with the LEDs to take up the rest of the potential?
Click to expand...

No, the meanwells are current drivers, meaning they adjust the voltage until the current is where is should be. 48v is just the maximum voltage they can put out.
 
crvz said:
my brain starting thinking this evening, so a question. I plan on running 8 LEDs on a meanwell eln-60-48D. Since the meanwell puts out 48V, and the LEDs are to run at ~3.3V, should I stick a resistor in series with the LEDs to take up the rest of the potential?
Click to expand...

No, the meanwells are current drivers, meaning they adjust the voltage until the current is where is should be. 48v is just the maximum voltage they can put out.
 
Finished my first LED panel last night. I've had everything for months now, yet finally got tired of being lazy and finished it. Only 60 LEDs more to go...
 
cyrusthevirus said:
My tought was to sut off one side so I could better dissipate the heat. If I keep it as a square, the air in the middle would be hotter than the outsides.
Click to expand...

Another reason why the squares are "worse" that you might think is that the inside surfaces are all essentially radiating IR right onto eachother, so half your surface area is totally wasted!

Dannyrotorpilot said:
By the way, any of you guys running a well ventilated full LED lighting having to use a chiller? I hope I dont have to with the cost of this setup.
Click to expand...

FWIW, I haven't exactly finished my big tank yet, but as I'm estimating the energy load it'll be running on, I'm much more worried that my heater will be running nostop than I am about needing a chiller. Besides being efficient overall and producing less heat than other types of lighting, LEDs produce their heat in a way that's much easier to get away from your tank water.

cyrusthevirus said:
I considered stud welding, because a friend of mine does it, but again, a lot of studs to add. The epoxy/tape is much easier.
Click to expand...

I'm no expert in the field, but I would be really paranoid that welding would result in warping/distortion of the surface - and since surface/surface contact is so critical for heat transfer, that would be a bad thing.
 
baja_01 said:
No, the meanwells are current drivers, meaning they adjust the voltage until the current is where is should be. 48v is just the maximum voltage they can put out.
Click to expand...

so even if I wire 1 LED in line, it will fire on the meanwell driver?
 
crvz said:
so even if I wire 1 LED in line, it will fire on the meanwell driver?
Click to expand...

Depends on who you ask. There are a few different datasheets out there that list different minimum voltages for correct operation. Basically, the chip inside the driver can only regulate down to a certain minimum voltage and still guarantee good current control. One LED is about 3 - 4v (depending on which LED you pick and which drive current) and the current datasheet on meanwell's product site lists 24v as the minimum for the ELN-60-48. But, other versions of the datasheet list a much much smaller minimum, and people have run them with a small number of LEDs, so it's kinda up in the air.
 
der_wille_zur_macht said:
Depends on who you ask. There are a few different datasheets out there that list different minimum voltages for correct operation. Basically, the chip inside the driver can only regulate down to a certain minimum voltage and still guarantee good current control. One LED is about 3 - 4v (depending on which LED you pick and which drive current) and the current datasheet on meanwell's product site lists 24v as the minimum for the ELN-60-48. But, other versions of the datasheet list a much much smaller minimum, and people have run them with a small number of LEDs, so it's kinda up in the air.
Click to expand...

Thanks, that's clearing it up. I did see that 24-48V range on the spec sheet, but I wasnt certain what it meant. I think I'll play it safe and run more than just a couple. Those LEDs are too expensive to burn them up!
 
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